happy new year every one.
My vehicle is a 1976 240D, I have been very satisfied with the car since I bought it five month and 5000 milles ago, last sunday after a 30 miles trip I parked the car in my drive way with the engine still running since I had to go back out shortly.When I got back out the engine was not running anymore and i was really surprised knowing that Ihad plenty of gas in the tank. I tried to resart it and it did right away but with some noise that I did not use to hear before,then I put it on reverse ,nothing happened put it on drive....nothing,checked tranny fluid it looked ok. Then I jacked up one rear wheel , when shifter on park wheel is locked ,in drive wheel turn and I cant stop it with foot , in reverse wheel turn and i was able to stop it with little pressure applied on the tire with my foot.
Any advice? Is the tranny gone or is that something fixable?
Thanks for your replies.

1975 240d
1976 240d

Didier